The present invention relates to a method for fabricating a protrusion, and more particularly to a method for fabricating a protrusion of a liquid crystal display.
The current trend is towards liquid crystal displays for achieving a larger panel size and a higher resolution. However, the characteristics of response time and wide-viewing angles of a liquid crystal display are still needed to be improved.
In order to improve the response time and the wide-viewing angles, a multi-domain vertically aligned (MVA) liquid crystal display is developed as shown in FIGS. 1(a) and (b). Liquid crystal molecules 13 around protrusions 12 which are formed on an upper substrate 10 and a lower substrate 11 are aligned with an advance inclination as shown in FIG. 1(a) by the protrusions 12. Therefore, when the liquid crystal molecules 13 are applied with an electric field, the liquid crystal molecules 13 are in the inclination state so that the response time and the wide-viewing angle are improved.
Please refer to FIGS. 2(a) and (b) showing protrusions 23 formed on a substrate 20. A positive photoresist layer 21 is coated on a substrate 20, i.e. a glass substrate, and then the positive photoresist layer 21 is exposed through a mask 22 as shown in FIG. 2(b). Subsequently, the exposed portion of the positive photoresist layer 21 is removed by development, and the remaining photoresist structure is formed as protrusions 23 as shown in FIG. 2(b).
However, the side walls of the protrusions 23 formed by the conventional fabricating processes could not be controlled to have the inclination in a triangular shape as shown in FIG. 1. Moreover, the protrusions formed by the conventional fabricating processes would cause the discontinuous alignment and the disclination lines of the liquid crystal molecules.
The present invention provides a method for fabricating a protrusion to overcome the foresaid drawbacks.
It is an object of the present invention to provide a method for fabricating a protrusion in a fabricating process of a liquid crystal display.
In accordance with the present invention, the method includes steps of providing a substrate pervious to light and having a first thickness, forming a photoresist layer having a second thickness on a first surface of the substrate, providing a photomask over a second surface of the substrate, performing a first exposure with a first exposing light on the photoresist layer with the photomask serving as a mask, wherein a first incident angle of the first exposing light is greater than zero degree, performing a second exposure with a second exposing light on the photoresist layer with the photomask serving as a mask, wherein a second incident angle of the second exposing light is greater than zero, and performing a development on the photoresist layer to remove a portion of the photoresist layer and form the protrusion on the first surface of the substrate.
Preferably, the substrate is a glass substrate.
Preferably, the photoresist layer is a positive photoresist layer.
Preferably, a light source of the exposure has parallel light. The light source is a laser beam. The parallel light is an ultraviolet ray.
Preferably, the pattern of the protrusion is controlled by the width of the photomask and the exposed angle.
Preferably, when the first incident angle and the second incident angle are respectively 30 degrees, a masking pattern of the mask has a width greater than at least 2/{square root over ( )}3 times the first thickness.
Preferably, the substrate is an array substrate of the liquid crystal display.
Preferably, the substrate is a color filter substrate of the liquid crystal display.
Preferably, the liquid crystal display is a multi-domain vertically aligned (MVA) liquid crystal display.
It is another object of the present invention to provide a method for forming a patterned photoresist layer, applying in fabrication of a liquid crystal display.
In accordance with the present invention, the method includes steps of providing a substrate pervious to light and having a first thickness, forming a photoresist layer having a second thickness on a first surface of the substrate, providing a photomask over a second surface of the substrate, performing a first exposure with a first exposing light on the photoresist layer with the photomask serving as a mask, wherein a first incident angle of the first exposing light is greater than zero degree, performing a second exposure with a second exposing light on the photoresist layer with the photomask serving as a mask, wherein the second exposing light has a second incident angle, and performing a development on the photoresist layer to remove a portion of the photoresist layer and form the patterned photoresist layer on the first surface of the substrate.
Preferably, the substrate is a glass substrate.
Preferably, the photoresist layer is a positive photoresist layer. The light source of the exposure has parallel light.
Preferably, the light source is a laser beam. The parallel light is an ultraviolet ray.
Preferably, the first incident angle and the second incident angle are respectively 30 degrees, a masking pattern of said mask has a width greater than at least 2/{square root over ( )}3 times said first thickness.
Preferably, the substrate is an upper and/or substrate of the liquid crystal display.
Preferably, the second incident angle is greater than zero degree.
In addition, the liquid crystal display is a multi-domain vertically aligned (MVA) liquid crystal display.
The present invention may best be understood through the following descriptions with reference to the accompanying drawings, in which: